[Experimental studies on the recovery of anesthetic gases]

The volatile anesthetic agents halothane, enflurane, and isoflurane are chlorofluorocarbons (CFC) and contribute to ozone depletion. Although the contribution is small, its importance is rising, as technical CFCs will be phased out according to the Montreal protocol (1987) and the London conference (1990) by the year 2000. Alternative procedures and CFC-free volatile agents such as des- and sevoflurane do not contribute to depletion of the ozone layer, but will not replace standard methods using volatile anesthetic agents in the near future. METHODS. In an experimental setup, we filtered anesthetic waste gases from scavenging systems of rebreathing circles by activated carbon filters. The filtered substances were desorbed by a heat chamber and condensed in a cold trap. RESULTS. By this method, it was possible to retrieve 50%-60% of the applied gases. Gas chromatographic analysis showed halothane containing traces of pollutants and isoflurane and enflurane as pure substances. DISCUSSION. The retrieval of anesthetic waste gases is easy; no sophisticated technical equipment is necessary. Purity of substances could make recycling possible and offer a method to avoid environmental pollution by volatile anesthetics.